This invention concerns runway lighting systems in which the marking lights are arranged in series along a looped primary circuit and specifically concerns a runway lighting system with reinforced insulation and waterproofing.
The runway lighting system used on airport runways generally consists of a looped primary circuit in series along which are connected marking lights powered by alternating current whose root mean square value is set by a constant current regulator depending on the desired brightness.
The marking lights are each isolated from the primary circuit by means of a marking light transformer whose essential characteristics are standardized. These current transformers are encapsulated in rubber and feature primary connection cords, on the supply side, as well as secondary connection cords, on the light side.
Several transformers of this type are generally installed in manholes which are in fact cavities in the ground next to the runway. A manhole can include up to 8 transformers as well as other additional equipment.
While drained, the manholes in which several transformers are installed are sometimes filled with rain water or run-off. As the transformers are placed in the manhole every which way, after a certain time in service and following maintenance, the length of the primary and secondary connection cords become a tangle of cables immersed and covered in mud which has accumulated over time in the bottom of the manhole.
The connections thus hang in the bottom of the manhole and consequently, even though the transformers are not in the water, the connectors and all of the cables are immersed in the bottom of the manhole.
The arrangement described above results in a certain number of major drawbacks. Firstly, the tangled cables increase the risk of connectors and plugs becoming disconnected. Even more so, as the equipment in the bottom of the manhole is often immersed and covered in mud, the identification of cables in relation to the transformers is difficult and represents a source of error when searching for the loop concerned, which can lead to wasted time, additional tests and possible damage.
Moreover, added to the fact that the encapsulation rubber and over-molding have a certain porosity which degrades with age, the major drawback is the poor watertightness of the connections. The penetration of water into the primary connectors leads to links with the ground which could damage the insulation or, through migration, destroy the transformer itself. The infiltration of water into the secondary connectors and plugs could lead to a certain derivation of the lamp current.
This is why the general purpose of the invention is to supply a reinforced insulated and waterproof runway lighting system by grouping the transformers located in each manhole into one single assembly.
Another purpose of the invention is to supply a runway lighting system in which each transformer features one male connector and one female plug so that several transformers can be grouped together to form a single multiple assembly mounted on the wall of the manhole.
The purpose of the invention is a runway lighting system, namely for an airport runway, including a power source supplying a constant current to a primary circuit and a plurality of marking lights connected respectively to the primary circuit by a plurality of current transformers, the secondary winding of which supplies the lamp current. A given number of adjacent marking lights are connected to the primary circuit respectively by a given number of transformers forming a multiple assembly without interconnecting cable, each transformer forming a single block having a male connector and a female plug. The transformers are stacked together to form the multiple assembly, the male connector of one of the transformers being inserted into the female plug of the immediately adjacent transformer. The multiple assembly is mounted in series in the primary circuit by means of two primary cords connected to the male connector of the first transformer of the multiple assembly and the female plug of the last transformer of the multiple assembly, respectively.